upstream simulation test suite flakyness

Hi, thanks for adding needs-internet restriction. I still sometimes see tests fail for what seems no obvious reason. Often on hard to debug platforms like armhf.

It seems that the wget and/or the tar (probably due corrupted content) fail. The PR here splits these command and makes them more verbose to more clearly see what is failing. At the same time I redirect stderr so that we can continue not to have allow-stderr.

Finally if those steps fail it isn't a real test fail, so I propose in that case to exit with the RC for skipping the test.